Hi Buck,can you post some photos of your lathe.The 918 ref is i believe from Warco and it may not be identical to the sieg C4.The large knob at the front disengages the drive to the chuck for when/if you are using the milling attachment.
When i say more torque i mean at the lowest speed about 100rpm the variable speed motor bogs down easily under load and its not slow enough for screw cutting. A hi/lo gear system would be good in lieu of the disengage. Tumbler reverse gears would be also good to reverse the leadscrew for LH threads etc

I'm interested in your brake idea, I suppose something could be rigged up similar to a spindle handle with the disc mounted to the expanding mandrel instead of the handle. Maybe a multi tool with both options.

Disc brakes from bikes would be extremely sufficient at stopping the lathe spindle even with a large piece in the chuck. (I've had enough times over the handle bars on my push bike to know that one). I dont however know what would happen to the lathe, wether long term use could damage something like the electronics board, trying to pump power to the motor while it's not turning due to the disc brake been applied. As an emergency brake I like the idea, but im sure there are other means.

Im going to apologize in advance for all the questions I have for you!
The gib screw that you intend to modify, it it on the operators side or the back side ?

What is the 918/920 and 9180 number stand for? Is it a particular series or model number or production number for the lathe?

Mine rungs at 100 rpm as verified by a separate hall effect sensor I have.
As I stated above in the other post, cant we just cahange the ratio of the drive belt/pulleys? If we can will the rpm readout be off or does this machine get its signal from a preprogrammed setting?

Lastly, could you show me where to find this info on the gearbox and dogclutch f from Marting Cleeve?

Again, sorry for all of the questions. I am eager to learn more about these machines and want to absorb anything I can find as there isnt much info on the web on the SC4. If there is, then I just dont know where to find it or how to search for it.

The three gib screws are on the rear of the slide of the saddle. So it is quite sensible to interspace 2 between them.

The 918/920 is for yet another 'Chinese' lathe that swings 9" and has either 18 or 20" between centers. However, it has a gear box- a bit clumsy but a gearbox. nevertheless. As it comes in the box, it has both chucks, a faceplate and both steadies as well as the ability to cut metric and imperial threads-- a bit too fast for me.

So Martin Cleeve. He had a ML4 beloved of JC Steam and did a lot of improvements which featured in Model Engineer and one was a dog clutch which appears both in Model Engineer and later in his excellent book 'Screwcutting in the Lathe' and this is still in print!

The gearbox mentioned is because the old Myford ML4 never had a gearbox and when Cleeve got fed up swopping cogs he made an outrider gear box which was published a long time ago in Model Engineer.

On the subject of the newer( then ML7) Cleeve appears to be unable to purchase a full blown ML7 but persuaded to get Myford to sell him a part machine so that he could use fast and loose pulleys drive a big 1HP motor but also a 1/3rd one.

What isn't so well known( now) is that he utilized lots of fabrications to make bits for both lathes and descriptions appeared in both Model Engineer and later in Engineering in Miniature.

We - that is Jim Early and myself tried to put this work on the 'net after Cleeves death but ran into copyright problems with the new masters of Model Engineer

Alas Brother Jim has reached the Grand Lodge above and I'm near enough the journey at almost 88 now to continue.

Beloved Cursed sworn at and very nearly belted with a hammer lol Norm I think the beloved is too strong a word

However the overdrive that Norm mentions is a clever device and would be able to be fitted as an add on to the sieg lathe with a modified cover, and an extra pulley added lower in the gear chain, an expanding mandrel that fits into the end of the spindle and carries a pulley, which can be engaged and disengaged by a quick slip of a vee belt.

JCSteam, youíre absolutely right. I didnít think about the electronic break. I wonder if it will be of any harm to the electronics or the motor. I do not know enough about electronics to rig up a switch that would deactivate the electronic braking while the disc brake is applied.
As far as any drawings or components go, I donít have any yet. I got the idea from a machinist or hobby forum, Iím not sure which one it was, Iíll have to look and post it here. Also ChrisB257 has two YouTube videos on adding a Bicycle disc brake to his lathe. He has an older lathe though.

Quote:

Originally Posted by JCSteam

I'm interested in your brake idea, I suppose something could be rigged up similar to a spindle handle with the disc mounted to the expanding mandrel instead of the handle. Maybe a multi tool with both options.

Disc brakes from bikes would be extremely sufficient at stopping the lathe spindle even with a large piece in the chuck. (I've had enough times over the handle bars on my push bike to know that one). I dont however know what would happen to the lathe, wether long term use could damage something like the electronics board, trying to pump power to the motor while it's not turning due to the disc brake been applied. As an emergency brake I like the idea, but im sure there are other means.

I will try and post some pictures tonight. Being Valentine's Day, I might get in trouble with the Girlfriend tho!! It’s a little machine shop part number 3595.

Quote:

Originally Posted by bazmak

Hi Buck,can you post some photos of your lathe.The 918 ref is i believe from Warco and it may not be identical to the sieg C4.The large knob at the front disengages the drive to the chuck for when/if you are using the milling attachment.
When i say more torque i mean at the lowest speed about 100rpm the variable speed motor bogs down easily under load and its not slow enough for screw cutting. A hi/lo gear system would be good in lieu of the disengage. Tumbler reverse gears would be also good to reverse the leadscrew for LH threads etc

That you for answering my questions. Some of it I have never heard of. I am going to start searching the web for these other lathes and people you speak of. Sorry for my last post. It was a bit hard to read which I just realized now. I was trying to respond to you on my cell phone and it didnt work out so well!
I do agree that more gib screws need to be added to the saddle. I will eventually add more gib screws to the cross slide and the compound.
There is a youtube video by dans-hobbies on change gears for the Chinese lathes. In the video he makes a new and improved bango for the change gears. He then added a set of gears to it so that he can more quickly switch between gear setups. While its not as fast as a gear box it is a little quicker. The lathe he has I believe is the next size of but most of the components are identical.

Quote:

Originally Posted by goldstar31

The three gib screws are on the rear of the slide of the saddle. So it is quite sensible to interspace 2 between them.

The 918/920 is for yet another 'Chinese' lathe that swings 9" and has either 18 or 20" between centers. However, it has a gear box- a bit clumsy but a gearbox. nevertheless. As it comes in the box, it has both chucks, a faceplate and both steadies as well as the ability to cut metric and imperial threads-- a bit too fast for me.

So Martin Cleeve. He had a ML4 beloved of JC Steam and did a lot of improvements which featured in Model Engineer and one was a dog clutch which appears both in Model Engineer and later in his excellent book 'Screwcutting in the Lathe' and this is still in print!

The gearbox mentioned is because the old Myford ML4 never had a gearbox and when Cleeve got fed up swopping cogs he made an outrider gear box which was published a long time ago in Model Engineer.

On the subject of the newer( then ML7) Cleeve appears to be unable to purchase a full blown ML7 but persuaded to get Myford to sell him a part machine so that he could use fast and loose pulleys drive a big 1HP motor but also a 1/3rd one.

What isn't so well known( now) is that he utilized lots of fabrications to make bits for both lathes and descriptions appeared in both Model Engineer and later in Engineering in Miniature.

We - that is Jim Early and myself tried to put this work on the 'net after Cleeves death but ran into copyright problems with the new masters of Model Engineer

Alas Brother Jim has reached the Grand Lodge above and I'm near enough the journey at almost 88 now to continue.

Wow! You guys have given me so much information! At the moment I need to get back to making a new spindle pulley for my Sieg X2 mill with a treadmill motor. I will read all of this and post back here. I almost torn between working on the lathe/mill or reading up on this new found info! Thanks!

Quote:

Originally Posted by JCSteam

Beloved Cursed sworn at and very nearly belted with a hammer lol Norm I think the beloved is too strong a word

However the overdrive that Norm mentions is a clever device and would be able to be fitted as an add on to the sieg lathe with a modified cover, and an extra pulley added lower in the gear chain, an expanding mandrel that fits into the end of the spindle and carries a pulley, which can be engaged and disengaged by a quick slip of a vee belt.